Technical Abstract:
The USDA’s sugarcane breeding program in Houma, LA was begun in 1929 to develop varieties adapted to the local growing region and to enhance disease resistance. In 1959, a sugarcane germplasm enhancement program was initiated to increase the diversity of germplasm in the commercial breeding program. This program was, and continues to be, aimed at broadening the genetic base of commercial varieties by introducing beneficial genes from wild relatives into the commercial gene pool. What became known as the “basic breeding program” is a long-term undertaking which utilizes a modified backcross breeding scheme. In 1993, LCP 85-384 was released as the first variety with origins in the basic breeding program. Novel F1 combinations are made between elite sugarcane varieties and relatives collected from the wild. Offspring from these crosses are evaluated in the field for five years after which superior materials are returned to the greenhouse and backcrossed into commercial sugarcane to increase sucrose concentration. Due to their status as a noxious weed, S. spontaneum accessions cannot be planted in the field, but hybrids between this species and sugarcane are permitted. While many first-generation hybrids are extremely vigorous, they are fibrous and do not contain enough sugar to be released as commercial sugarcane. In the past, this material had to be backcrossed to sugarcane multiple times for offspring to be considered for commercial release, but with the emergence of a biofuels industry, some early generation hybrids are now being considered as “energy cane”. With the biofuels industry in its infancy, and the ideal feedstock composition and conversion technology unknown, the SRUs breeding program has taken a two-pronged approach to energy cane variety development. Type I energy canes, containing both high fiber (>14%) and commercial sucrose, and Type II energy canes, containing high fiber (20-30%) and very little sucrose, are being developed. Ho 02-113 (Type II), released by the USDA in 2010, had average yields of 71 tons of cane per acre (25.9 tons of dry weight) and 26% fiber across 4 crop cycles when grown alongside sugarcane in Schriever, LA. Percent Many energy cane varieties from the USDA-ARS Sugarcane Research Unit in Houma, LA are being evaluated in regions north of the commercial sugarcane growing areas as far north as Booneville, AK (35o8’23” N). Some varieties are proving to be well adapted and appear to possess higher cold tolerance than commercial sugarcane.